A thermosetting urethane elastomer is prepared from:
(a) a prepolymer having isocyanate groups at terminal ends obtained by allowing p-phenylene diisocyanate to react with a compound having 2 or more active hydrogens, and
(b) curing agents of 1,4-bis(2-hydroxyethoxy)benzene and trimethylolpropane or 1,4-bis(2-hydroxyethoxy)benzene and a polyol having isocyanurate ring.
|
1. A thermosetting urethane elastomer having improved heat resistance and compression set properties prepared from:
(a) a prepolymer having isocyanate groups at terminal ends obtained by allowing p-phenylene diisocyanate to react with a compound having 2 or more active hydrogens, and (b) a curing agent selected from the group consisting of i. 1,4-bis(2-hydroxyethoxy)benzene and trimethylolpropane, and ii. 1,4-bis(2-hydroxyethoxy)benzene and a polyol having an isocyanurate ring. 2. A thermosetting urethane elastomer according to
3. A thermosetting urethane elastomer according to
4. A thermosetting urethane elastomer according to
5. A thermosetting urethane elastomer according to
6. A thermosetting urethane elastomer according to
7. A thermosetting urethane elastomer according to
8. A thermosetting urethane elastomer according to
9. A thermosetting urethane elastomer according to
10. A thermosetting urethane elastomer according to
11. A thermosetting urethane elastomer according to
12. A thermosetting urethane elastomer according to
13. A thermosetting urethane elastomer according to
14. A thermosetting urethane elastomer according to
15. A thermosetting urethane elastomer according to
16. A thermosetting urethane elastomer according to
17. A thermosetting urethane elastomer according to
18. A thermosetting urethane elastomer according to
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
This is a continuation of copending application Ser. No. 07/267,444 filed on 11/4/88, now abandoned.
1. Field of the Invention
This invention relates to a thermosetting urethane elastomer, more particularly to a thermosetting urethane elastomer prepared from a prepolymer containing isocyanate groups at terminal ends obtained from p-phenylene diisocyanate (hereinafter abbreviated as PPDI) and a polyol and a curing agent comprising specific polyols.
2. Related Background Art
Thermosetting urethane elastomers are generally produced according to (a) the method in which a prepolymer contaInIng Isocyanate groups at terminal ends derived from a diisocyanate such as tolylene diisocyanate, diphenylmethane diisocyanate (hereinafter abbreviated as MDI), hexamethylene diisocyanate, etc. and a polyol such as polyether polyol, polyester polyol or polycaprolactone polyol, etc. is cured with a curing agent of a glycol such as 1,4 -butylene glycol (hereinafter abbreviated as 1,4-BG) or an amine such as 3,3'-dichloro-4,4'-diaminodiphenyl-methane, or (b) the method in which an unstable prepolymer derived from 1,5-naphthalene diisocyanate (hereinafter abbreviated as NDI) and a polyester polyol is rapidly cured with a glycol such as 1,4-BG, etc.
These thermosetting urethane elastomers are highly elastic, having excellent tensile strength, etc., and have been widely used for rolls, solid tires, belts, etc. However, the elastomer obtaIned in the above method (a) is inferior in heat resistance to be greatly changed in hardness depending on the temperature, and therefore unsuitable for use in a place which becomes elevated temperature or a place where the temperature is greatly changed. On the other hand, the prepolymer obtained in the above method (b) is excellent in heat resistance, but since an unstable prepolymer is used, drawbacks are involved in equipment during production and restriction in time.
The present inventors, in order to improve heat resistance, change in physical properties depending on temperature of thermosettIng urethane elastomers, have studied and investigated intensively about combinations of various prepolymers containing isocyanate groups at terminal ends comprising diisocyanate and polyol with various curing agents, and consequently found that they can be improved by a combination of a specific diisocyanate with a specific curing agent, to accomplish the present invention.
According to the present invention, there is provided a thermosetting urethane elastomer prepared from:
(a) a prepolymer having isocyanate groups at terminal ends obtained by alloWing PPDI to react with a compound having 2 or more active hydrogens, and
(b) curing agents comprising 1,4-bis(2-hydroxyethoxy)benzene (hereinafter abbreviated as BHEB) and trimethylolpropane (hereinafter abbreviated as TMP) or BHEB and a polyol having isocyanurate ring.
In the present invention, as the result of investigation about the starting materials for improving heat resistance of thermosetting urethane elastomers, it has been found that PPDI is preferable as the diisocyanate . PPDI is an aromatic diisocyanate having isocyanate groups at the 1- and 4-positions on the benzene ring, and its melting point is 95°C
Such prepolymer containing isocyanate groups at terminal ends obtained from PPDI and polyol was cured with various curing agents, and heat resistance and temperature dependency, etc. of the cured product were measured. As the result, by use of BHEB and TMP or BHEB and a polyol having isocyanurate ring as the curing agents, a thermosetting urethane elastomer having excellent physical properties was obtained.
The thermosetting urethane elastomer consisting only of said prepolymer and BHEB, although excellent in heat resistance, has the drawback that its compression set is large. The thermosetting urethane elastomer according to the present invention is also improved in compression set simultaneously with heat resistance.
The compounds having two or more active hydrogens which can be used for obtaining the prepolymer having isocyanate groups at terminal ends in the present invention have an average molecular eight of 62 to 6000, preferably 1000 to 3000. Among them, polyester polyol, polyether polyol, polycarbonate polyol, polyacrylic polyol, polyamine, etc. are included.
As the polyester polyol, there may be employed polyester polyols obtained by polycondensation of glycol such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-BG, 2,2-dimethyl 1,3 -propane diol, diethylene glycol, 1,5-pentane diol, 3-methyl-1,5-pentane diol, 1,6-hexane diol, cyclohexane-1,4-diol, cyclohexane-1,4 -dimethanol, etc. alone or a mixture of these with a dibasic acid such as succinic acid, maleic acid, adipic acid, glutaric acid, pimellic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic acid, hexahydroisophthalic acid, etc. alone or a mixture of these, and, acid esters, acid halides of these, and mixtures of these polyester polyols and the above glycols, and further lactone type polyols such as polycaprolactone diols obtained by subjecting lactones such as ε-caprolactone, etc. to ring-opening addition polymerization in the presence of a glycol, etc.
As the polyether polyol, there may be employed hydroxyl-containing polyether polyols made by the addition polymerization of alkylene oxide such as ethylene oxide, propylene oxide, etc. to glycols such as ethylene glycol, 1,2-propylene glycol, diethylene glycol, polyethylene glycol, etc., polyols having 3 or more functional groups such as glycerine, trimethylolethane, TMP, pentaerythritol, etc., polyamines such as ethylenediamine, toluenediamine, etc., either alone or as a mixture of two or more kinds.
Further, as the polycarbonate polyol, it can be obtained by the reaction of a dialkyl carbonate, an alkylene carbonate or a diaryl carbonate, etc. with a hydroxyl compound, for example, 1,4-BG, 1,6-hexane diol, etc., and these can be also used either alone or as a mixture of two or more kinds.
The curing agents which can be used in the present invention are BHEB and TMP or BHEB and a polyol containing isocyanurate ring, etc. The mole ratio of BHEB and TMP or BHEB and the polyol containing isocyanurate ring ranges from 9.5:0.5 to 1,9, preferably from 9:1 to 2:8. The ratio influences various physical properties of thermosetting urethane elastomer such a hardness, tensile strength, compression set etc. Accordingly, any thermosetting urethane elastomer having desired properties can be prepared by changing the above mentioned ratio.
As said polyol containing isocyanurate ring, there may be included tris-β-hydroxyethylisocyanurate (hereinafter abbreviated as THEIC) and/or a polyol containing isocyanurate ring obtained by addition of 1 to 3 moles of caprolactone to 1 mole of THEIC, for example, Placcel E-212 produced by Daicel Co.
Such polyol containing isocyanurate ring is represented by the following formula (1): ##STR1## where l, m, n=0∼1, 0≦l+m+n∼3.
The preparation of the prepolymer having isocyanate groups at terminal ends in the present invention can be typicaly practiced according to such methods as follows.
(A) By use of a twin screw extruder, solid PPDI and a liquid polyol are fed quantitatively at a predetermined molar ratio at a cylinder temperature of 70° to 180°C to carry out continuous synthesis.
(B) A predetermined amount of a polyol is charged into the reaction batch, and after adjustment of temperature range from 100° to 130° C., a predetermined amount of PPDI is charged under solid state and synthesis is carried out under stirring.
(C) A predetermined amount of solid PPDI and a part of a polyol are charged into the reaction batch, and while the reaction is carried out at 70 to 100°C the remainder of the polyol is charged in several divided portions, and synthesis is carried out while repeating the reaction.
It is required that the reaction between the organic polyisocyanate and the active hydrogen-containing compound should be conducted so that the isocyanate group content in the prepolymer should be 2 to 20% by weight, preferably 3 to 10% by weight. If the isocyanate content in the prepolymer obtained becomes greater than 20% by weight, free PPDI becomes increased in amount, whereby storage stability of the prepolymer will be inferior. On the other hand, if it is smaller than 2% by weight, the isocyanate content as the prepolymer is low and the viscosity becomes very high, whereby the prepolymer can be handled with difficulty.
The thermosetting urethane elastomer of the present invention can be prepared by setting the NCO equivalent of said prepolymer and the OH equivalent of the curing agent at a ratio of 1:0.8 to 1:0.95, adjusting said prepolymer temperature at 110° to 130°C, the curing agent temperature at 110° to 120°C and the mold temperature at 120° to 130°C, stirring predetermined amounts of the prepolymer and the curing agents, and degassing the mixture under reduced pressure prior to casting into the mold, followed by heating for 8 to 15 hours. When a dispersing machine is to be used, it is necessary to perform degassing under reduced pressure before mixing the prepolymer with the curing agent.
According to the present invention, heat resistance and lowering in physical properties by temperature, etc. which have been the drawbacks of the thermosetting urethane elastomer could be improved by a composition comprising a prepolymer containing isocyanate groups at terminal ends by use of PPDI as the diisocyanate and, as the curing agents, BHEB and TMP or BHEB and a polyol containing isocyanurate ring. Particularly, in the physical properties, also concerning compression set which has been deemed to be improved with difficultly, it could be also improved to better than the performance exhibited by the thermosetting urethane elastomer of the prior art.
The thermosetting urethane elastomer of the present invention can broaden its uses to the place which becomes elevated temperatures or the place where the temperature change is great, where thermosetting urethane elastomers could not be employed in the prior art. Specific examples of such uses may include roll for paper making, printing roll and rolls for other OA instruments, further cleaning blade, various belts, O-ring, sealing material such as bush, vibration insulator, solid tire, wheel for caster, snow plow, etc.
The present invention is described below in more detail by referring to Examples. In Examples, "parts" and "%" are respectively "parts by weight" and "% by weight", unless otherwise noted.
PAC Synthesis of prepolymerPPDI which is solid at ordinary temperature at a ratio of 0.288 mol/min. and a polycaprolactone polyol (average molecular weight 2000, functionality 2) heated to 80°C at a ratio of 0.144 mol/min. were fed into a twin-screw extruder at a screw rotational number of 150 rpm, with cylinder temperatures of 80°C at the feed portion, 120° to 150°C at the middle portion and 80°C at the outlet portion, to obtain a prepolymer. The prepolymer was found to have an NCO content of 3.6%.
BHEB/TMP at a weight ratio of 5.80/1.00 was completely mixed and dissolved at 120°C to provide a curing agent.
The above prepolymer and the curing agent were adjusted to 110°C and a mold to 120°C, 100 g of the prepolymer and 6.8 g of the curing agent were well stirred and poured into the mold after degassing under reduced pressure. After casting, heating was effected at 120° C. for 10 hours to obtain a thermosetting urethane elastomer. The urethane elastomer was left to stand at 25°C for 7 days, and then provided for various tests. The results are shown in Table 1 (physical properties under normal state, hereinafter the same), Table 2 (heat aging test, hereinafter the same) and Table 3 (temperature dependency of hardness, hereinafter the same).
PAC Synthesis of prepolymerThe prepolymer obtained in Example 1 was used.
BHEB/E-212*1) at a weight ratio of 1.26/1.00 was completely mixed and dissolved to provide a curing agent.
The above prepolymer and the curing agent were adjusted 110°C and a mold to 120°C, 100 g of the prepolymer and 10.4 g of the curing agent were well stirred and poured into the mold after degassing under reduced pressure. After casting, heating was effected at 120°C for 10 hours to obtain a thermosetting urethane elastomer. The urethane elastomer was left to stand at 25°C for 7 days, and then provided for various tests. The results are shown in Table 1 to Table 3.
*1) Polyol containing isocyanurate ring, produced by Daicel Co.
PAC Synthesis of prepolymerPPDI which is solid at ordinary temperature at a ratio of 0.505 mol/min. and a polytetramethylene glycol (average molecular weight 1000, functionality 2) heated to 80°C at a ratio of 0.253 mol/min. were fed into a twin-screw extruder at a screw rotational number of 150 rpm, with cylinder temperatures of 80°C at the feed portion, 120° to 150°C at the middle portion and 80°C at the outlet portion, to obtain a prepolymer. The prepolymer was found to have an NCO content of 6.3%.
By use of the curing agent in Example 1, the above prepolymer and the curing agent were adjusted to 110°C and a mold to 120°C, 100 g of the prepolymer and 12.0 g of the curing agent were well stirred and poured into the mold after degassing under reduced pressure. After casting, heating gas effected at 120°C for 10 hours to obtain a thermosetting urethane elastomer. The urethane elastomer was left to stand at 25°C for 7 days, and then provided for various tests. The results are shown in Table 1 to Table 3.
PAC Synthesis of prepolymerThe prepolymer obtained in Example 3 was used.
The curing agent shown in Example 2 was used.
The prepolymer and the curing agent were adjusted to 110°C and a mold to 120°C, 100 g of the prepolymer and 18.2 g of the curing agent were well stirred and poured into the mold after degassing under reduced pressure. After casting, heating gas effected at 120°C for 10 hours to obtain a thermosetting urethane elastomer. The urethane elastomer was left to stand at 25°C for 7 days, and then provided for various tests. The results are shown in Table 1 to Table 3.
As the prepolymer, &he same prepolymer as in Example 1 was employed.
The prepolymer was adjusted to 75°C, 1,4-BG to 25°C and a mold to 120°C, and 100 g of the prepolymer and 3.7 g of 1,4-BG were well stirred and poured into the mold after degassing under reduced pressure. After casting, heating was effected at 120°C for 5 hours to obtain a thermosetting urethane elastomer. The urethane elastomer was left to stand at 25°C for 7 days, and then provided for various tests. The results are shown in Table 1 to Table 3.
As the prepolymer, the same prepolymer as in Example 3 was employed.
Under the same temperature conditions as in Comparative example 1, 100 g of the prepolymer and 6.4 g of 1,4-BG were well stirred and poured into the mold after degassing under reduced pressure. After casting, heating was effected at 120°C for 5 hours to obtain a thermosetting urethane elastomer. The urethane elastomer was left to stand at 25°C for 7 days, and then provided for various tests. The results are shown in Table 1 to Table 3.
PAC Synthesis of prepolymerInto a four necked round bottomed flask equIpped with a stirrer, a thermometer, a pipe for nitrogen seal, etc., 2.00 mol of MDI and 1.00 mol of a polycaprolactone polyol (average molecular weight 1,000, functionality 2) were charged and the reaction was carried out under nitrogen seal at 65° to 75°C for 3 hours. The prepolymer obtained was found to have an NCO content of 5.6%.
Under the same temperature conditions as in Comparative example 1, 100 g of the prepolymer and 5.7 g of 1,4-BG were well stirred and poured into the mold after degassing under reduced pressure. After casting heating was effected at 120°C for 5 hours to obtain a thermosetting urethane elastomer. The urethane elastomer was left to stand at 25°C for 7 days, and then provided for various tests. The results are shown in Table 1 to Table 5.
Into the same round bottomed flask as in Comparative example 3 was charged 1.00 mol of a polyethylene adipate (average molecular weight 2000, functionality 2) and the temperature was adjusted to 120°C To the polyethylene adipate was added 2.00 mol of solid NDI, and the reaction was carried out under stirring without heating until the temperature became 90°C The prepolymer obtained was found to have an NCO content of 3.5%.
The prepolymer was adjusted to 100°C, 1,4-BG to 25°C and a mold to 120°C and 100 g of the prepolymer and 3.6 g of 1,4-BG were well stirred and poured into the mold after degassing under reduced pressure. After casting, heating was effected at 120°C for 6 hours to obtain a thermosetting urethane elastomer. The urethane elastomer was left to stand at 26°C for 7 days, and then provided for various tests. The results are shown in Table 1 to Table 3.
PAC Synthesis of prepolymerThe prepolymer obtained in Comparative example 3 was used.
By use of the curing agent of Example 1, and similarly under the same temperature conditions as in Example 1, 100 g of the prepolymer and 10.3 g of the curing agent were well stirred and poured into the mold after degassing under reduced pressure. After casting, heating was effected at 120°C for 10 hours to obtain a thermosetting urethane elastomer. The urethane elastomer was left to stand at 25°C for 7 days, and then provided for various tests. The results are shown in Table 1 to Table 3.
PAC Synthesis of prepolymerPPDI which is solid at ordinary temperature at a ratio of 0.437 mol/min. and a polycaprolactone polyol (average molecular weight 1200, functional group number 2) heated to 80°C at a ratio of 0.219 mol/min. were fed into a twin-screw extruder at a screw rotational number of 150 rpm, with cylinder temperatures of 80°C at the feed portion, 120° to 150°C at the middle portion and 80°C at the outlet portion, to obtain a prepolymer. The prepolymer was found to have an NCO content of 5.5 %.
PAC Synthesis of prepolymerThe prepolymer obtained in Example 5 was used.
Synthesis of prepolymer
The prepolymer obtained in Example 1 was used.
PAC Resin formationThe resin formation in Examples 5∼10 was carried out by change of the ratio of BHEB/TMP or BHEB/E-212 as shown in Table 4 in which the ratio of the prepolymer to the curing agent are further shown. The procedure for the casting to mold and the conditions after molding were the same as in Example 1. Table 5 shows the physical properties under normal state of the thermosetting urethane elastomers obtained in Examples 5∼10.
| TABLE 1 |
| __________________________________________________________________________ |
| No. |
| Example Comparative example |
| Item 1 2 3 4 1 2 3 4 5 |
| __________________________________________________________________________ |
| Hardness (JIS.A) |
| 85 84 94 93 92 97 82 91 89 |
| 100% Modulus |
| 59 46 121 |
| 106 |
| 86 125 |
| 85 69 77 |
| (Kg/cm2) |
| 300% Modulus |
| 165 |
| 88 213 |
| 167 |
| 113 |
| 149 |
| 165 |
| 100 |
| 224 |
| (Kg/cm2) |
| Tensile strenngth |
| 427 |
| 472 |
| 217 |
| 294 |
| 387 |
| 352 |
| 519 |
| 361 |
| 525 |
| (Kg/cm2) |
| Elongation (%) |
| 380 |
| 550 |
| 300 |
| 440 |
| 830 |
| 780 |
| 600 |
| 850 |
| 380 |
| Tear strength1 |
| 68 72 82 88 139 |
| 133 |
| 140 |
| 112 |
| 69 |
| (Kg/cm) |
| Compression set2 (%) |
| 29 20 29 28 45 34 35 29 41 |
| Bashore Rebound |
| 73 73 67 62 69 66 43 55 21 |
| elasticity (%) |
| __________________________________________________________________________ |
| Measurement method: according to JIS K6301 |
| 1 Test strip: Btype |
| 2 Conditions: 25% compression, 70°C × 22 Hr |
| TABLE 2 |
| ______________________________________ |
| Lapse of time |
| 3 1 2 4 8 |
| No. days week weeks weeks weeks |
| ______________________________________ |
| Example 1 109.0 100.4 |
| 83.8 52.4 48.4 |
| 2 105.5 98.9 85.5 56.6 46.8 |
| 3 74.3 55.4 45.0 39.9 35.1 |
| 4 72.9 56.8 45.3 40.8 33.4 |
| Comparative |
| 1 82.5 50.8 34.9 33.6 21.1 |
| example 2 53.3 31.6 24.5 22.2 18.5 |
| 3 70.4 43.3 29.2 20.0 17.5 |
| 4 89.9 68.3 35.5 35.0 33.3 |
| 5 103.1 96.2 62.9 31.2 20.0 |
| ______________________________________ |
| Measurement method: according to JIS K6301 |
| Heat aging test (150°C), Tensile strength retentivity |
| TABLE 3 |
| ______________________________________ |
| No. |
| Measurement Example Comparative example |
| temperature 1 2 3 4 1 2 3 4 5 |
| ______________________________________ |
| Hardness |
| -25°C |
| 90 88 95 93 99 98 93 94 99 |
| (JIS.A) 25°C |
| 85 84 94 93 92 97 82 91 89 |
| 70°C |
| 82 82 94 93 90 95 77 88 84 |
| 120°C |
| 81 81 93 92 89 93 74 87 80 |
| 150°C |
| 79 79 93 92 84 90 67 81 75 |
| ______________________________________ |
| Measurement method: according to JIS K6301 |
| TABLE 4 |
| __________________________________________________________________________ |
| No. |
| Example |
| 5 6 7 8 9 10 |
| __________________________________________________________________________ |
| Curing |
| Composition |
| BHEB/TMP |
| BHEB/TMP |
| BHEB/TMP |
| BHEB/TMP |
| BHEB/E-212 |
| BHEB/E-212 |
| agent |
| Ratio by |
| 13.29/1.00 |
| 5.90/1.00 |
| 3.44/1.00 |
| 1.48/100 |
| 1.30/1.00 |
| 0.08/1.00 |
| weight (The |
| (9/1) (8/2) (7/3) (5/5) (8/2) (2/8) |
| value in |
| parentheses |
| shows mole |
| ratio) |
| Resin |
| Prepolymer |
| 100 100 100 100 100 100 |
| for- |
| (parts) |
| mation |
| Curing 11.4 10.5 6.3 5.4 10.4 15.3 |
| agent |
| (parts) |
| __________________________________________________________________________ |
| TABLE 5 |
| __________________________________________________________________________ |
| No. |
| Example |
| Item 5 6 7 8 9 10 |
| __________________________________________________________________________ |
| Prepolymer |
| PCL-1200/ |
| PCL-1200/ |
| The same |
| The same |
| The same |
| The same |
| PPDI PPDI as in as in as in as in |
| (R=2) (R=2) Example 1 |
| Example 1 |
| Example 1 |
| Example 1 |
| Curing agent |
| BHEB/TMP |
| BHEB/TMP |
| BHEB/TMP |
| BHEB/TMP |
| BHEB/E-212 |
| BHEB/E-212 |
| (mole ratio) |
| = 9/1 = 8/2 = 7/3 = 5/5 = 8/2 = 2/8 |
| Hardness |
| 95 90 80 70 85 60 |
| (JIS.A) |
| 100% 99 93 48 28 46 16 |
| Modulus |
| (kg/cm2) |
| 300% 129 149 201 -- 88 38 |
| Modulus |
| (kg/cm2) |
| Tensile |
| 631 524 286 140 472 196 |
| strength |
| (kg/cm2) |
| Elongation |
| 500 450 330 270 550 400 |
| (%) |
| Tear1 |
| 111 89 57 34 72 26 |
| strength |
| (kg/cm) |
| Compression |
| 23 17 24 8 20 0 |
| set (%) |
| Bounce 65 64 72 71 73 78 |
| impact |
| elasticity (%) |
| __________________________________________________________________________ |
| 1 The test conditions are the same as that in Table 1. |
Sato, Susumu, Kawasaki, Masahiro, Maeda, Yoshiaki, Ohbuchi, Yukio
| Patent | Priority | Assignee | Title |
| 11584873, | Nov 14 2017 | HONDA MOTOR CO , LTD | Sealing member and vibration damping device including the same |
| 5450184, | Jun 07 1990 | Canon Kabushiki Kaisha | Cleaning blade for electrophotography, cleaning device for electrophotography, apparatus unit, electrophotographic apparatus and facsimile apparatus |
| 5496496, | Feb 18 1992 | Mitsui Takeda Chemicals, INC | Process for producing polyurethane elastomers |
| 5618904, | Dec 29 1993 | Essex Specialty Products, Inc | Polyurethane hot melt adhesive |
| 5795948, | May 26 1992 | Bayer Aktiengesellschaft | Multistage process for production of thermoplastic polyurethane elastomers |
| 5840233, | Sep 16 1997 | Optimer, Inc.; OPTIMER, INC | Process of making melt-spun elastomeric fibers |
| 6277942, | Sep 16 1997 | Optimer, Inc. | Melt-spun elastomeric fibers and the preparation thereof |
| 6392002, | May 14 1999 | JPMORGAN CHASE BANK, N A , AS SUCCESSOR ADMINISTRATIVE AGENT | Urethane golf ball |
| 6964626, | Jul 14 1994 | Gates Corporation | High temperature polyurethane/urea elastomers |
| 8720921, | Oct 30 2012 | SuperSprings International, Inc. | Vehicular suspension enhancement |
| 8733746, | Jul 28 2008 | SuperSprings International, Inc. | Vehicular suspension enhancement |
| Patent | Priority | Assignee | Title |
| 3016364, | |||
| 3658746, | |||
| 3716519, | |||
| 4086211, | Mar 14 1975 | Bridgestone Tire Company Limited | Method of producing polyurethane products having an improved flex crack resistance |
| JP4721592, | |||
| JP4925427, | |||
| JP6059249, |
| Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
| Jun 27 1990 | Nippon Polyurethane Industry Co., Ltd. | (assignment on the face of the patent) | / |
| Date | Maintenance Fee Events |
| Dec 02 1994 | M183: Payment of Maintenance Fee, 4th Year, Large Entity. |
| Jan 20 1995 | ASPN: Payor Number Assigned. |
| Jun 11 1996 | ASPN: Payor Number Assigned. |
| Jun 11 1996 | RMPN: Payer Number De-assigned. |
| Nov 02 1998 | M184: Payment of Maintenance Fee, 8th Year, Large Entity. |
| Dec 18 2002 | REM: Maintenance Fee Reminder Mailed. |
| Jun 04 2003 | EXP: Patent Expired for Failure to Pay Maintenance Fees. |
| Date | Maintenance Schedule |
| Jun 04 1994 | 4 years fee payment window open |
| Dec 04 1994 | 6 months grace period start (w surcharge) |
| Jun 04 1995 | patent expiry (for year 4) |
| Jun 04 1997 | 2 years to revive unintentionally abandoned end. (for year 4) |
| Jun 04 1998 | 8 years fee payment window open |
| Dec 04 1998 | 6 months grace period start (w surcharge) |
| Jun 04 1999 | patent expiry (for year 8) |
| Jun 04 2001 | 2 years to revive unintentionally abandoned end. (for year 8) |
| Jun 04 2002 | 12 years fee payment window open |
| Dec 04 2002 | 6 months grace period start (w surcharge) |
| Jun 04 2003 | patent expiry (for year 12) |
| Jun 04 2005 | 2 years to revive unintentionally abandoned end. (for year 12) |